US President Donald Trump's businesses lost over $1 billion from 1985 to 1994 and he avoided paying income taxes for eight of the 10 years, according to US media.

RNA - Trump’s core businesses, including casinos, hotels and apartment buildings, lost $1.17 billion over a decade, The New York Times reported.

The newspaper said it obtained printouts from Trump's official Internal Revenue Service (IRS) tax transcripts.

Trump posted losses in excess of $250 million in both 1990 and 1991, which appeared to be more than double any other individual US taxpayer, the Times said.

The report comes amid a fresh battle between Democrats in Congress and the Trump administration over the release of the president’s tax returns.

US Treasury Secretary Steven Mnuchin on Monday denied a request by US Representative Richard Neal, the Democratic chairman of the House of Representatives Ways and Means Committee, for Trump’s tax returns.

Democrats want Trump’s tax data as part of their investigations of possible conflicts of interest posed by his continued ownership of extensive business interests, even as he serves as president.

Trump, a real estate magnate who turned over the running of his businesses to his sons after his election in 2016, touted his business acumen and negotiating skills on the campaign trail.

Trump broke with a decades-old precedent by refusing to release his tax returns as a presidential candidate in 2016 or since being elected, saying he could not do so while his taxes were being audited.